Forward Scattering of Light from a Laboratory Plasma

Measurement of the Electron Correlation Spectrum in a Plasma

“…Although other experimenters have found indications of this narrowing, they have been unable to measure the spectral shape for various reasons: insufficient resolution 2 "" 4 ; scattered intensity small compared with background 4 ' 5 ; erratic laser frequency. 5 In the work reported here, these problems were overcome. Resolution was sufficient to study the strong narrow ion-correlated band, and the signal-to-bremsstrahlung ratio was sufficient to measure weak spectral components over a broad range corresponding to electron thermal velocities.…”

Collective Scattering of Laser Light by a Plasma

“…The commonly used phenomenological potentials for helium cannot be expected to yield this value for the phonon velocity because they do not adequately represent the interaction for values of r significantly smaller than the equilibrium interatomic separation, nor are they intended to. For example, the familiar 6-12 potential does not even pos-Several authors 1 " 5 have reported experiments on the scattering of laser light from electrons in a laboratory plasma. The profiles of the scattered light show a nearly Gaussian distribution, indicating little or no collective effect between the ions and the electrons.…”

“…1 "" 4 The occurrence of localized states of relatively long lifetime into a continuum of levels raises, in fact, a number of problems for the theory of solids. 5 The suggestion that optical transitions to higher excited states from the fundamental level of the F center were responsible for the absorption of the L bands in alkali halides was made by Luty 6 on the basis of proportionality among L, K, and F bands. However, the proportionality between the F and K bands has been at times doubted, 7 and the ratio between the height of F and L bands in crystals x rayed at low temperature is only approximately equal to that found in additive-tain a theoretical curve whose peaks coincide with the experimental peaks as shown in Fig.…”

The Evolution of Light Scattering as a Plasma Diagnostic

“…They succeeded in reducing the stray scattered light to a low enough level so that the detector could be absolutely calibrated by a measurement of Rayleigh scattering from nitrogen. Two weeks later, U. Ascoli-Bartoli, J. Katzenstein, and L. Lovisetto at the Frascati Laboratory, Italy, reported observation of the unresolved ion feature in scattered light from a theta pinch at a scattering angle of 3 • [28], and in the next year reported a resolved ion feature spectrum from which an ion temperature of 50 eV was deduced [28]. Although the measured spectra were not well resolved, they compared well with the theoretical spectral profiles for plasmas with the spectroscopically determined temperature and density.…”